Here are some shows I can think of that have a good amount of expletives

Hellsing Ultimate series
Black Lagoon series
Deadman Wonderland
We Without Wings
High School DxD
Gantz
Highschool of the Dead
Puni Puni Poemy
Samurai Champloo
Accel World
Air Gear
Basilisk
Gantz
Panty & Stocking with Garterbelt
Higurashi series
Hell Girl
Most 1990s-era Manga dubs
Durarara!! series
Full Metal Panic! series